1. Field Of The Invention
The present invention relates generally to a temperature measuring circuit employing a thermistor and, more particularly, to a method and a circuit for linearizing the output of a non-linear thermistor.
2. Description Of The Prior Art
It is well known to use a thermistor as a transducer for the measurement of temperature. However, commonly-available thermistors typically exhibit a non-linear coefficient of resistance change with changes in sensed temperature. In many applications, it is desirable that the voltage output of a thermistor temperature measuring circuit be a linear function of temperature. One typical prior art method for approximately linearizing thermistor output is including the thermistor in a voltage divider network with suitable fixed resistors connected both in series with and in parallel with the thermistor. Another method is employing a plurality of matched or complementary thermistors exposed to the same sensed temperature and connected so that their non-linear characteristics cancel out over a useful temperature range. However, various prior art thermistor linearizing methods and circuits have disadvantages such as difficulty of adjustment and limited operational temperature range without undue complexity.